1. Field
Described herein is an improved floatation device. The device such as a surfboard does not utilise a stringer as traditionally used and instead used a low density foam layer as the core of the device.
2. Description of the Related Art
Flotation devices such as surfboards have been made more many years, the design of the board gradually altering as new materials and techniques become available.
US publication number 2010/0240271 provides detailed synopsis of the history of surfboard manufacture and in the interests of brevity, this publication is referred to and incorporated herein.
To summarise, surfboards are traditionally manufactured from a blank comprising two polyurethane (PU) foam sections and a wooden or foam ‘stringer’ extending from the nose of the board to the tail which gives structure to the board. PU foam alone lacks the structural integrity required as it is bendy up to a point and then fails dramatically. A stringer is traditionally added in order to reduce the board flex and thereby minimise board breakage and improve board performance. Stringer designs typically represent the best compromise between strength and board dynamics. Despite use of a stringer or stringers, board breakage is still a common occurrence, particularly in larger waves or when the board strikes a hard feature such as rocks or coral reef.
Methods to address board breakage yet still maintain the desired flex and performance of a board have varied.
US2010/0240271 noted above illustrates one method being to incorporate a carbon fibre layer or layers within the board. This publication also teaches about the need to vary the curvature of the carbon fibre core relative to the curvature of the top surface. The publication also still shows and uses a stringer or stringers and does not necessarily do away with the need for such stiffening parts.
A further problem with traditional stringer designs is that the board top and bottom surfaces (top or deck and base or underside or waterside) have the stringer flush or extending from the surrounding foam. This makes shaping the board difficult as two varying materials need to be shaped rather than one continuous smooth surface.
In the marine boat building industry, composite designers determined early on that sandwiching a low-density, lightweight core material between thin face sheets can dramatically increase a laminate's stiffness with little added weight. A sandwich structure is cost-effective because the relatively low-cost core replaces more expensive composite reinforcement material and can be cured with the skins in one-shot processes like resin infusion. The stiffer but lighter sandwich panel requires less supporting structure than a solid laminate. Marine composites typically only refer to matching a high density foam with a fiberglass sheet or epoxy sheet in the wall of a boat or similar application. Further layers such as expanded polystyrene (EPS) that might be used in surfboard applications are not discussed in marine/boat applications since this added layer is unnecessary and is a surfing specific application hence marine art tends to lead away from surfboard manufacture.
For the purpose of this specification the term ‘comprise’ and grammatical variations thereof shall have an inclusive meaning—i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements.
Further aspects and advantages of the process and product will become apparent from the ensuing description that is given by way of example only.